


Miyu's Massive Messy Mistress

by Gothdresser



Category: Fate/kaleid liner PRISMA ILLYA
Genre: BBW, Cuck, Cucking, Cuckoldry, Dependency, F/F, Fat - Freeform, I can't believe I actually wrote a story about cuckoldry, Pantypoop, Scat, Soiling, bedmessing, cuckold, diapermessing, messing, pooping
Language: English
Status: Completed
Published: 2020-04-22
Updated: 2020-04-22
Packaged: 2021-03-01 21:39:38
Rating: Mature
Warnings: Underage
Chapters: 1
Words: 2,424
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23784028
Author URL: https://archiveofourown.org/users/Gothdresser/pseuds/Gothdresser
Summary: Miyu's maidhood extends past just serving Luvia as the little girl helps her overweight not-so-little friend with her morning diaper change, although Chloe has to make do when she loses her chance to do the change herself.
Relationships: Miyu Edelfelt/Chloe von Einzbern | Kuro, Miyu Edelfelt/Illyasviel von Einzbern
Comments: 1
Kudos: 7





	Miyu's Massive Messy Mistress

Pulling on a pull-up, her thigh highs, and a pair of mary janes, the young raven-haired girl quietly closed the mansion’s door before heading right across the street. Although she was employed as a maid for Lady Luvia, Miyu had to admit she had a much more favorable mistress right across the street, one that she maybe had been helping out a little too much. Even the girl’s actual familial maids treated Miyu like a regular at the household and she pretty much was at this point since Miyu always tried to be as loyal as she could, every single morning.

She had to wake up early enough before another resident of the household got up to check on her sister, resulting in a certain smugness that Miyu enjoyed a little too much when Chloe witnessed the maid lifting up Illya’s obese stomach to get to her diaper tapes. Yes, Illya had gained more than just a few pounds as Miyu had to make her dependent somehow, inviting her out for sweets after school or feeding her extra desserts during lunch, all up until the white-haired girl was more than triple her weight and Miyu found out just fat Illya was when her best friend completely ruined her panties in class.

The visual effects were obvious enough and Miyu found herself creaming her own panties while she watched Illya’s sag down in the middle of class when she tried to waddle her big fat ass to the bathroom. All eyes were on Illya’s huge butt as her ass let a massive mess rip into her underwear, bad enough that it even managed to almost reach her knees with the panties exposed under her ill-fitting skirt. No one but Illya could have made such noises anyways since Illya was the only obese not-so-little girl among them and there had already been rumors about her clogging the girls’ bathroom multiple times. Even their loud-mouthed teacher was speechless when Illya’s ass finally stopped pooping before Miyu headed over to her.

And while that was Illya’s first time having an accident, it was also the first time that she had stolen an opportunity from Chloe when she rushed over almost right away to escort the stinky not-so-little girl to the nurse’s office before Chloe even got permission from Taiga to do so. Wiping Illya’s ass was not only satisfying in getting to do it in the first play but also with the thought that it made Illya thank her instead of relying on anyone else to bring the wet wipe between the fatass’s thick dirty asscheeks. The nurse said she wasn’t legally allowed to and so as they waited for Sella to come to pick them up, Miyu set more of the foundation for Illya’s dependence on her.

There were somehow panties in Illya’s size in the nurse’s office but Miyu made sure to go with her to the store right after they were excused from school to pick up XL diapers for the 11-year-old girl. Miyu had also slipped in some pull-ups for herself just in case she couldn’t control herself again down there, something that proved useful since she woke up to a sticky bed every morning for the first week after that incident. Her control was better now but wearing some sort of padding helped out when she was premature, and Miyu had to admit that Illya’s smile was pretty cute when she found out that she wasn’t the only one wearing a diaper.

Speaking of diapers, Miyu didn’t even bother holding her nose as a gross but familiar scent wafted to her nose before she could even open Illya’s door. Good, that meant that Chloe hadn’t gotten to Illya yet as Miyu entered the room as quietly as she could. Even if she was about to wake her anyway, there was one cute little trick that she liked to do to the sleepy girl whose pajamas couldn’t even cover her big pale tummy nor the waistband of her diaper. Just burying her face in it was tough to resist but at least she began to rub Illya’s stomach, eliciting groans from the sleepy girl while her tummy was sloshed from side to side. “Come on, Illya, please wake up. You know we have school today and I still have to change your diaper.”

Pulling down her sheets because she knew Illya’s tendency to want to curl back up in them, Miyu clenched at seeing just how obvious Illya’s diaper was underneath her pink pajama bottoms, especially due to how full it was. And as Illya grumbled from having her tummy squished, her face scrunched up while Miyu felt herself leaking from the sound of another kind of squishing loudly filling the room. If she wasn’t careful, she might end up needing a change before Illya did, but even soiling herself again didn’t wake Illya up until the door flew open behind them.

“Illyaaaa! Pee-ew, did you mess the bed again? You should be glad I’m here to change your- Aww, I’m too late again…” For yet another morning in a row, Chloe pouted as she looked the maid up and down. She just wanted to change her sister’s diaper and tease her, and yet it felt like she kept getting denied the chance to. “Come on, don’t you think I can handle Illya’s morning diaper change for once? Don’t you ever take a break from cleaning her butt?” Only at night, it seemed but Sella was a little too careful after some previous incident of her going into Illya’s room at night.

Although before Miyu could retort about her duty to her best friend, the white-haired girl was leaning up in bed while rubbing her eyes. “Don’t be so loud, I was sleeping, Chloe… Aw jeez, did I go potty this much again?” It took Illya a few moments and a little help from Miyu but she managed to sit up in bed with distinct squelching coming from under her couple of hundred-pound butt. Some girls dealt with bedwetting as they neared a pubescent age, but completely decimating a diaper after a pair of messes through the night wasn’t all too common for any age or gender. Wiggling her butt to the tune of squishing did bring about an important matter though. “Say, Miyu, sorry for the mess, but I think I need a change really soon…”

Helping her sit up also made a tougher clean-up for Miyu but the little maid didn’t mind it one bit at all. She’d gladly change any and all of Illya’s diapers, no matter how full and dirty they were. There was a reason why Illya trusted her so much and also why Illya referred to her right away instead of Chloe. “See, your sister even wants me to change her. You probably wouldn’t even be able to untape her before you start molesting her diaper.”

“Y-y-you don’t know anything of what I’d do for Illya! Maybe I just want to change my sister’s diaper for once, j-jeez.” Miyu just had to be too spot-on, huh, as Chloe’s face turned bright red. Sure, she had been wanting to play with Illya’s diaper because how could anyone not want to do so, but being called out on it when she thought she had a chance this morning hurt. Although in an odd way today since despite being denied the opportunity she had been trying so hard for, Chloe felt a small throb in the front of her panties at the thought of Illya getting her diaper changed by someone else. “Fine, go change her diaper before she gets a rash, I don’t want to hear her complaining about it later.”

Miyu couldn’t help but think about how haughty Chloe was trying to be there, but all she gave was a nod as Illya’s twin exited the room. Closing the door was obvious enough but Miyu did hear an extra bang against the door oddly enough. Whatever, she had more important issues to attend to, namely the double-messed diaper underneath Illya’s pajamas. “Let me help you out with that before you strain yourself too much.” A third accident might be a little too much for both the diaper and Miyu’s peepee, doing her best to calm herself down as she pulled off Illya’s pajamas to get quite the intimate look at her. Even as a fatty, a lack of total weight distribution kept her budding breasts practically the same size, looking even flatter compared to the belly that partially hid the front of her diaper now that Illya was sitting up. “I’m almost afraid you might need a size up. Just look at how full your diaper is despite these having the best capacity for your size.”

Illya was at such a good size though that Miyu sort of didn’t want to risk her gaining too much weight, and she could figure something out to make sure that Illya didn’t leak any poopy at her current level. Maybe that’d be pretty cute too but she’d have to get Illya out of this diaper first. The unpeeling of the tapes was a nice sound to hear before Miyu pulled open the front of the diaper, lifting Illya’s muffintop up to wipe against her crotch and Illya’s small cock twitching under the towelette could make her die of cuteness. Another bump at the door turned her attention in that direction, but Illya’s groaning quickly brought her back to what she was supposed to be doing. “Oh, are you alright, Illya? Is something wrong?”

“It’s alright, I think I’m just a little hungry. I hope Sella made cinnamon buns for breakfast again.” How cute, Illya was already thinking of food when it was practically in one end and out the other for the overweight little girl. Miyu only chuckled a little as she kept working on the super poopy diaper, wet wipe after wet wipe piling up as she felt how thick Illya’s lardass was. It made sense why Chloe wanted to do this so much, but this was her job and Miyu didn’t particularly feel like sharing this with anyone else. Slipping her diaper out from under the huge ass, it took all of Miyu’s strength to turn Illya on her side to clean her up there as well.

At least Illya being on her side made it easier to position the new diaper and Miyu gently lowered her back before applying an ample amount of baby powder. Rashes were important to prevent as Chloe mentioned and Miyu liked to be diligent about keeping Illya’s huge adorable butt from getting any as she softly rubbed Illya crotch and butt until it was whiter than it already was. Once finished, all that was left was pulling the front of the diaper past the huge meaty pillars that were her thighs and tugging on the tapes to make sure Illya was snug in her diaper. A couple of checks around the leak guards proved secured and she patted the front of the padding to signal the end of Illya’s change, letting her hand linger there. “All done! How does that feel, Illya? Anything else you need before I get your uniform?”

A moment of hesitation did worry Miyu though as Illya blushed and stuttered out, “W-well, I kind of, y-you know… You just ch-changed me but I gotta… Going potty!” With Miyu’s hand still on her padded crotch, the front quickly grew warm before Illya’s moans were loudly drowned out by yet another mess so far. A fresh diaper was barely swaddled around her waist before Illya filled it up, her legs fidgeting as she gripped the bed. “Sorry, Miyu. You just changed my diaper but I couldn’t hold it and I didn’t want to poop while the diaper was open…”

“I-it’s…” Huffing out, Miyu struggled to catch her breath as her knees threatened to buckle. “It’s fine, I guess I’ll just, uh… change you after breakfast, you’ll probably need one before we head to school. If you’ll just excuse me for a moment.” Struggling to walk towards the door, Miyu could feel the squishiness in the front of her pull-up as the warmth lingered on her hand. To think that Chloe wanted her to share this feeling seemed crazy, and Miyu was glad that she wore a pull-up.

However, as she headed to the door to check how bad she squirted in her pull-up, another thud came from behind the door. Instead of opening it right away, Miyu pressed her ear against it and heard an all-too-familiar voice on the other side muttering something. “I-I can't believe Miyu got to change her again... A-and I can hear Illya crapping herself, and I don't even get to watch! B-but... G-gah, why is that so... H-hot~" Miyu wished she could doubt who it was but swung the door open anyway to confirm as strawberry hair tilted back to meet each other’s eyes.

Miyu had been too busy dealing with Illya’s change and messes to properly check who was thudding against the door but it seemed that she caught Chloe at just the perfect time. Witnessing her master’s sister playing with her small cock was one thing, but seeing her squirt to her sister’s diaper change was another. There was no way that Chloe could hide this incident when the white sticky proof was on the front of her nightie, and although it was disgusting to see, Miyu couldn’t help but chuckle a little at the sight.

Poor poor Chloe, hehe. While she could have easily ratted Chloe out, maybe there was a way for her to share Illya with her sister, even if a little twisted. Crouching down next to Chloe, Miyu kept her voice to a low whisper. “Aww, did you enjoy the sounds of Illya’s diaper change that much? Maybe I’ll let you sit in on one, but I’m Illya’s maid unless you want me to tell your mom about this little incident. I can loan you a pull-up if you need, or maybe I’ll let you wear one of Illya’s dirty diapers if you help me out. I have to dress Illya now though, so have fun cleaning up… cuck~”

With that, Miyu closed the door and went back in to help Illya out, caring not so much about her own pull-up anymore. Cruelty wasn’t something she was too particularly fond of, but Illya was hers and Miyu wouldn’t let anyone take her fatty messy master away from her. No matter what!~


End file.
